Vehicle security systems are widely used to deter vehicle theft, prevent theft of valuables from a vehicle, deter vandalism, and to protect vehicle owners and occupants. A typical automobile security system, for example, includes a central processor or controller connected to a plurality of vehicle sensors. The sensors, for example, may detect opening of the trunk, hood, doors, windows, and also movement of the vehicle or within the vehicle. Ultrasonic and microwave motion detectors, vibration sensors, sound discriminators, differential pressure sensors, and switches may be used as sensors. In addition, radar sensors may be used to monitor the area proximate the vehicle.
The controller typically operates to give an alarm indication in the event of triggering of a vehicle sensor. The alarm indication may typically be a flashing of the lights and/or the sounding of the vehicle horn or a siren. In addition, the vehicle fuel supply and/or ignition power may be selectively disabled based upon an alarm condition.
A typical security system also includes a receiver associated with the controller that cooperates with one or more remote transmitters typically carried by the user as disclosed, for example, in U.S. Pat. No. 4,383,242 to Sassover et al. The remote transmitter may be used to arm and disarm the vehicle security system or provide other remote control features from a predetermined range away from the vehicle.
As disclosed in U.S. Pat. No. 5,049,867 to Stouffer and U.S. Pat. No. 5,146,215 to Drori, the security system controller may include features to store and compare unique codes associated with a plurality of remote transmitters, each remote transmitter having its own unique code initially programmed therein. U.S. Pat. No. 5,146,215 in particular discloses that remote transmitter codes may be added or deleted from the controller corresponding to the number of remote transmitters desired by the user. Unfortunately, a would-be thief gaining access to the controller may readily enter the program or learn mode and install the code of an unauthorized remote transmitter. The owner would thus be unaware of such activity, until the thief returns with the unauthorized remote transmitter to disarm the security system and steal the vehicle, or steal the vehicle contents.
U.S. Pat. No. 5,654,688, assigned to the assignee of the present application, discloses a significant advance in the area of vehicle security, particularly as it relates to ensuring the number of authorized remote transmitter. The patent discloses identifying the number of remote transmitters coded to operate the vehicle security system and giving this indication so that the user is informed if an unauthorized remote transmitter has been added.
It may also be desirable to extend the range from which a remote transmitter will operate. In the past an antenna has been positioned in the upper passenger compartment, such as the window of the vehicle, to increase the effective control range.
There are also other desirable features of many conventional vehicle security systems, such as the ability to place the system in a valet mode so that others may use the vehicle without triggering the alarm. Typically a valet switch is positioned so as to be hidden in an area not readily visible in the vehicle. The user may operate the valet switch to enter the valet mode and exit the valet mode. In addition, the valet switch also has been used to permit the user to stop an alarm, such as when the user loses a remote transmitter or the battery fails, for example. The hidden valet switch may be awkward to operate and may also be of limited security value, since there are only so many places to position such an important switch within the vehicle.
The assignee of the present invention has also provided other advantageous features, such as an easier to use valet switch, wherein the user can toggle in or out of the valet mode as long as the alarm controller is in the disarmed mode. To permit the valet switch to operate without a code, the assignee of the present invention has also provided a coded override switch which requires the user to enter a code to disarm the system when an alarm is sounding.